Certain constructions involving piles require that the head of the pile member have lateral dimensions which are greater than those of the pile member. For example, with a pile member having a circular cross-section, the diameter of the pile head can exceed that of the pile member by a factor of three or more. Such assemblies are useful in the support of stepped beams spanning the gaps between neighboring pile members, the beams having upwardly directed steps on which floor panels or blocks can be supported.
One method of forming piles with enlarged heads, which is described in U.S. Pat. No. 5,070,672, drives a hollow casing into the ground to form an opening which tapers downwardly and inwardly. The hollow casing can have an upper section, an intermediate section which tapers inwardly and downwardly, and a bottom section which tapers inwardly and sharply downwardly. After the casing has been driven into the ground so that its top is at ground level, a pile member is positioned within the hollow of the casing and then driven into the ground below the casing. After the pile member has been driven downwardly so that its top end is located at a pre-arranged depth within the casing, the casing is removed and the resulting hole around the upper end of the pile member is filled with concrete to form a pile head. Thus, the pile head has an inverted generally conical configuration from which the pile member extends downwardly into the ground. While this method is advantageous in many situations, in certain circumstances this method can be disadvantageous as the pile forming technique calls for at least the pile head to be formed in situ, almost invariably by the pouring of concrete into a preformed hole. As it is often difficult to ensure that the concrete is delivered at exactly the required time and as the pouring and setting of concrete depends to an extent on weather conditions, it is sometimes desirable that the pouring of concrete to form elements on site be avoided, or at least minimized.
It is an object of the present invention to obviate or mitigate these and other disadvantages.